WO2017036173A1

WO2017036173A1 - Optical proximity correction method and system

Info

Publication number: WO2017036173A1
Application number: PCT/CN2016/081701
Authority: WO
Inventors: 万金垠; 王谨恒; 张雷; 陈洁
Original assignee: 无锡华润上华半导体有限公司
Priority date: 2015-09-02
Filing date: 2016-05-11
Publication date: 2017-03-09
Also published as: US20180252996A1; US10521546B2; CN106483758A; CN106483758B

Abstract

An optical proximity correction method, comprising: dissecting an edge of a design pattern (120/220) to form segments (Seg1/Seg2); setting target points of the segments (Seg1/Seg2), and if the segments (Seg1/Seg2) translate in a direction vertical to the segments (Seg1/Seg2), controlling tangent points (P1/P2) of the segments (Seg1/Seg2) tangent to a simulated pattern (110/210) to coincide with the target points; computing edge position differences of the target points; and correcting the design pattern (120/220) according to the edge position differences.

Description

Optical proximity effect correction method and system

[Technical Field]

The present invention relates to the field of semiconductor manufacturing technology, and in particular, to an optical proximity effect correction method and system.

【Background technique】

In the semiconductor manufacturing process, as the lithography size becomes smaller and smaller, resolution enhancement technology (RET, resolution enhancement) Technique) is commonly used. Among them, below the 180nm technology node, optical proximity effect correction technology in RET technology (OPC, optical proximity) Correction) is adopted as a conventional technical means. In the revision process, two methods are often used, one is called rule-based OPC, and the other is model-based OPC (MBOPC, Model Based OPC); when selecting MBOPC In the method, the design graphic is dissectioned into a plurality of relatively short segments, and then the target position points of the respective segments are set (Target) Point), evaluate OPC by introducing Edge Positionment Error (EPE), which is the difference between the analog value and the target value at the target position point. The result of each correction loop. When the statistical value of the EPE of all the segments in the layout reaches a certain range, all the line segments are considered to be placed; this placement process generally needs 3-8. Repeated calculations of the rounds ensure that the EPE statistics of all segments in the layout reach a certain range.

The conventional optical proximity effect correction method is generally fixed for the position of the target position of the line segment, for example, the center of each line segment or the end of the line segment. This kind of fixed placement makes the adaptability to different design graphics insufficient, and there is usually a problem of insufficient correction or excessive correction, resulting in low correction accuracy.

[Summary of the Invention]

Based on this, it is necessary to provide an optical proximity effect correction method that can effectively improve the correction accuracy. In addition, an optical proximity correction system is also provided.

A method for correcting optical proximity effects, comprising:

Segmenting the edges of the design graphic to form a line segment;

Setting a target position point in the line segment, if the line segment is translated in a direction perpendicular to the line segment, the tangent point of the line segment and the simulated graphic will coincide with the target position point;

Calculating a difference in edge position of the target position point;

The design graphic is corrected according to the edge position difference.

An optical proximity effect correction system comprising:

a segmentation module for segmenting edges of the design graphic to form a plurality of line segments;

a setting module, configured to set a target position point in the line segment; if the line segment is translated in a direction perpendicular to the line segment, the line tangent point of the line segment and the simulated graphic coincides with the target position point;

a calculation module, configured to calculate a difference in edge position of the target position point; and

And a correction module, configured to correct the design graphic according to the edge position difference.

In the above optical proximity effect correction method and system, the setting manner of the target position point of the line segment is no longer fixed, but is changed with the graphic, and the curve end point of the analog figure corresponding to the line segment is usually selected as the reference position of the target position point. The end point of the curve can be judged as follows: If the line segment is translated in the vertical direction of the line segment, the tangent point of the line segment and the simulated figure is the end point of the curve, and the end point of the curve coincides with the target position point. For this line segment, the EPE at the corresponding position of the end point of the curve is usually the largest, and the image correction according to the EPE can effectively reduce the number of corrections, reduce the degree of correction or correction, and make the simulation result more closely match the target value, and improve the correction. Efficiency and correction accuracy.

[Description of the Drawings]

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the embodiments or the description of the prior art will be briefly described below. Obviously, the drawings in the following description are only It is a certain embodiment of the present invention, and those skilled in the art can obtain drawings of other embodiments according to the drawings without any creative work.

1 is a flow chart of an optical proximity effect correction method;

Figure 2 is a schematic view of the correction of excess;

Fig. 3 is a schematic view of the case where the correction is insufficient.

【detailed description】

In order to facilitate the understanding of the present invention, the present invention will be described more fully hereinafter with reference to the accompanying drawings. Preferred embodiments of the invention are shown in the drawings. However, the invention may be embodied in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that the understanding of the present disclosure will be more fully understood.

All technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs, unless otherwise defined. The terminology used in the description of the present invention is for the purpose of describing particular embodiments and is not intended to limit the invention. The term "and/or" as used herein includes any and all combinations of one or more of the associated listed items.

Fig. 2 is a schematic view showing an excessive correction. The graphic 110 (solid line) is an analog graphic, the graphic 120 (dashed line) is a design graphic, and the graphic 110 is a graphic simulated according to the graphic 120. In the conventional optical proximity effect correction method, usually, the intermediate position 130 of the line segment Seg1 is fixedly set to the target position point. As can be seen from the figure, at the intermediate position 130, the pattern 110 and the pattern 120 are almost fitted positions, and thus the intermediate position 130 EPE will obviously be relatively small. After correcting the graph by EPE, the image will be changed little, so the correction efficiency is low and the correction accuracy is not high.

Fig. 3 is a schematic view of the case where the correction is insufficient. The graphic 210 is an analog graphic, the graphic 220 is a design graphic, and the graphic 210 is a graphic simulated according to the graphic 220. In the conventional optical proximity effect correction method, the target position point is usually fixedly set at the intermediate position 230 of the line segment Seg2. As can be seen from the figure, at the intermediate position 230, the pattern 210 and the pattern 220 are almost in a fitting position, and thus the intermediate position 230 EPE will obviously be relatively small. After correcting the graph by EPE, the image will be changed little, so the correction efficiency is low and the correction accuracy is not high.

In the conventional optical proximity effect correction method, the manner of fixedly setting the target position point needs to be improved. The following describes a method for correcting the optical proximity effect of the target position point. The specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

1 is a flow chart of an optical proximity effect correction method.

An optical proximity effect correction method comprising the steps of:

Step S100: dividing an edge of the design graphic to form a plurality of line segments. Optical proximity correction technique (OPC, optical Proximity correction) The program is configured to perform a dissection on the outside of the design graphic, and divide the design graphic into a plurality of segments.

Step S200: setting a target location point in the line segment.

The target position point is judged as follows: if the line segment is translated in a direction perpendicular to the line segment, the tangent point of the line segment and the simulated figure will coincide with the target position point. Referring to Fig. 2, P1 is the tangent point, and position 140 is the target position point set by the method. Referring to Fig. 3, P2 is the tangent point, and position 240 is the target position point set by the method. Usually all the line segments that are divided are set to the corresponding target position points, and then the overall correction of the figure is performed. When the EPE of each segment meets the requirements, the correction can be ended.

The setting of the target position point is related to the simulated graphic, usually at the end of the vertical direction of the line segment of the analog graphic. Therefore, the position of the target position point can be confirmed by the above-described determination method. When the above judgment method is employed, there may be a case where a plurality of tangent points exist. When the line segment is translated in the direction perpendicular to the line segment, if there is more than one tangent point between the line segment and the simulated pattern, the corresponding tangent point coincides with the target position point when the line segment translation distance is maximum. Usually, the distance between the simulated graphic and the designed graphic is not too far apart, so when the line segment is translated in the direction perpendicular to the line segment, the translation distance of the line segment is within a preset range to avoid misjudgment. For example, the line segment is one end of a rectangular figure. If the line segment is translated to the other end of the rectangle, it will cause misjudgment, so the translation distance needs to be limited.

The above determination method is only one method of defining the position of the target position point, and does not mean that any of the above determination methods must be present in step S200.

Step S300: Calculate the edge position difference (EPE) of the target position point. The target position point is set by step S200, and the edge position difference of the target position point is usually the largest for the line segment.

Step S400: Correcting the design graphic according to the edge position difference. Since the difference of the edge position of the target position point is the largest, the number of corrections can be effectively reduced, the degree of correction is insufficient or the degree of correction is reduced, the simulation result is more matched with the target value, and the correction efficiency and the correction precision are improved.

After the step S400 is completed, it is determined whether the edge position difference is within the first set range. If not, returning to the step of performing the segmentation of the edge of the design graphic to form a plurality of line segments, repeating the above step S200 ~ Step S400, until the edge position difference is within the first set range, the correction is ended, and the final corrected pattern is obtained.

An optical proximity effect correction system applied to the above correction method will be described below.

An optical proximity effect correction system for use in a semiconductor manufacturing process, comprising:

A segmentation module for segmenting edges of the design graphic to form a plurality of line segments. According to the OPC program setting, the outside of the design graphic is analyzed and divided (Dissection), and the design graphic is divided into a plurality of segments.

Set the module to set the target position point in the online segment.

If the line segment is translated in the vertical direction of the line segment, the tangent point of the line segment and the simulated figure coincides with the target position point. Referring to Fig. 2, P1 is the tangent point, and position 140 is the target position point set by the above correction method. Referring to Fig. 3, P2 is the tangent point, and position 240 is the target position point set by the above correction method. Usually all the line segments that are divided are set to the corresponding target position points, and then the overall correction of the figure is performed. When the EPE of each segment meets the requirements, the correction can be ended.

The setting of the target position point is related to the simulated graphic, usually at the end of the vertical direction of the line segment of the analog graphic. Therefore, the position of the target position point can be confirmed by the above-described determination method. When the above judgment method is employed, there may be a case where a plurality of tangent points exist. When the line segment is translated in the vertical direction of the line segment, if there is more than one tangent point between the line segment and the simulated figure, the corresponding tangent point coincides with the target position point when the line segment translation distance is maximum. Usually, the distance between the simulated graphic and the designed graphic is not too far apart. Therefore, when the line segment is shifted in the vertical direction of the line segment, the translation distance of the line segment is within a preset range to avoid misjudgment. For example, the line segment is one end of a rectangular figure. If the line segment is translated to the other end of the rectangle, it will cause misjudgment, so the translation distance needs to be limited.

The above determination method is only one method of defining the position of the target position point, and does not mean that the setting module must perform any of the above determination methods.

A calculation module for calculating the difference in edge position of the target position point. The target position point is set by step S200, and the edge position difference of the target position point is usually the largest for the line segment.

A correction module for correcting the design graphic based on the difference in edge position. Since the difference of the edge position of the target position point is the largest, the number of corrections can be effectively reduced, the degree of correction is insufficient or the degree of correction is reduced, the simulation result is more matched with the target value, and the correction efficiency and the correction precision are improved.

It should be understood that although the various steps in the flowchart of FIG. 1 are sequentially displayed as indicated by the arrows, these steps are not necessarily performed in the order indicated by the arrows. Except as explicitly stated herein, the execution of these steps is not strictly limited, and may be performed in other sequences. Moreover, at least some of the steps in FIG. 1 may include a plurality of sub-steps or stages, which are not necessarily performed at the same time, but may be executed at different times, and the order of execution thereof is not necessarily This may be performed in sequence, but may be performed alternately or alternately with other steps or at least a portion of the sub-steps or stages of the other steps.

It can be understood that the illustrations in FIGS. 2 to 3 are also a simple example of a part of the figure in the process of the optical proximity effect correction method, and do not represent the entire structure of the figure.

The above-mentioned embodiments are merely illustrative of several embodiments of the present invention, and the description thereof is more specific and detailed, but is not to be construed as limiting the scope of the invention. It should be noted that a number of variations and modifications may be made by those skilled in the art without departing from the spirit and scope of the invention. Therefore, the scope of the invention should be determined by the appended claims.

Claims

A method for correcting optical proximity effects, comprising:

Segmenting the edges of the design graphic to form a line segment;

Setting a target position point in the line segment, if the line segment is translated in a direction perpendicular to the line segment, controlling a line tangent point of the line segment and the simulated graphic to coincide with the target position point;

Calculating a difference in edge position of the target position point; and

The design graphic is corrected according to the edge position difference.
The method according to claim 1, wherein the plurality of line segments are plural, and corresponding target position points are set in all of the line segments.
According to claim 1 The method is characterized in that if there is more than one tangent point between the line segment and the simulated graphic, the corresponding tangent point coincides with the target position point when the line segment translation distance is maximum.
The method according to claim 1, wherein the step of correcting the design graphic according to the edge position difference further comprises the steps of:

Determining whether the edge position difference is within the first set range, and if not, returning to performing the step of dividing the edge of the design pattern to form a plurality of line segments, and if so, ending the correction.
An optical proximity effect correction system comprising:

a segmentation module for segmenting edges of the design graphic to form a plurality of line segments;

a setting module, configured to set a target position point in the line segment; if the line segment is translated in a direction perpendicular to the line segment, the line tangent point of the line segment and the simulated graphic coincides with the target position point;

a calculation module, configured to calculate a difference in edge position of the target position point; and

And a correction module, configured to correct the design graphic according to the edge position difference.
According to claim 5 The optical proximity effect correction system is characterized in that the setting module sets corresponding target position points in all the line segments.
According to claim 5 The optical proximity effect correction system, wherein if the line segment is translated in a direction perpendicular to the line segment, if the line segment has more than one tangent point with the simulated pattern, the line segment shifts The tangent point corresponding to the maximum distance coincides with the target position point.